Cooling ducts for disc brake caliper and method of manufacture thereof

ABSTRACT

The present invention relates to a disc brake caliper body comprising a mounting side bracket and a non-mounting side bracket extending along a circumferential direction of the body, each bracket being configured to hold at least one brake pad. In order to provide improved cooling efficiency while maintaining the required stability of the brake caliper, the caliper body further comprises at least one cooling duct formed by additive manufacturing, at least one cooling duct being an integral part of the caliper body.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to United Kingdom Patent ApplicationNo. 1618402.0, filed Oct. 27, 2016. The disclosure set forth in thereferenced application is incorporated herein by reference in itsentirety.

The present invention relates to a disc brake caliper comprising atleast one cooling duct and a method of manufacturer thereof. Morespecifically, the present invention is concerned with a disc brakecaliper body comprising at least one cooling duct formed by additivemanufacturing.

Brake calipers are well known in the art. Such calipers are arranged toactuate a pair of opposed brake pads to clamp a brake disc therebetween.Clamping of the brake disc retards motion of a vehicle to which thecaliper is attached. Brake calipers come in various forms. For example,pin-slider type calipers utilise a cylinder or cylinders on a singleside of the disc to advance one of the two opposed pads. Once the pad isin contact with the disc, the caliper (which is slidably mounted formovement in the direction of actuation) slides such that the opposingpad also contacts the disc to clamp it between the pads. Opposed-pistontype calipers, which are more common in motor sports, have a staticcaliper with two post banks of cylinders, each of which advances arespective brake pad. As such, the caliper remains static but the discis clamped between moving parts. In both cases, the general principle isthe same—hydraulic pressure is increased in a cylinder to force twobrake pads together to clamp a disc.

Known calipers comprise a brake caliper body which provides the strengthand stiffness required to react to forces experienced under braking. Thecaliper body typically has two brackets, one either side of the plane ofthe brake disc, each bracket housing respective brake cylinders withassociated pistons. Brake pads are mounted on a laterally inner faceside of the caliper body for advancement towards the disc by pistonswithin the cylinders. The brackets are connected by one or more bridgemembers extending across, thereby straddling, the disc. Hydraulic fluidpassages are attached to, and machined into, the caliper body to supplyhydraulic fluid to the cylinders. For example, in a known brake caliper,an external hydraulic conduit is provided on the radial outer surface ofone of the bridge members spanning the caliper. The conduit is placed influid communication with a passage drilled into the bracket extending tothe cylinder.

The brake caliper bodies tend to be mounted to the vehicle at an inboardor body side (which is known as the mounting side bracket). The opposingbracket is known as the non-mounting side bracket.

Brake calipers tend to get very hot in use due to friction between thepads and disc when breaking loads are applied. Especially in racingcars, it is known that overheated brake calipers and discs will reducethe ability to slow the car and severely decrease durability of thebrakes. In order to prevent overheating of the brake system, it is knownto use air conduits in racing cars that route air flow towards aninboard side of the brake disc (rotor), which will increase the air flowrate through the brake rotor vanes, which in turn cool the rotor faster.The brake caliper body, on the other hand, can comprise separate coolingfluid channels which may be machined into the caliper body for thecommunication of cooling fluid, be that air, water or specific coolantaround the brake caliper.

Conventionally known cooling ducts run coolant fluid around the caliperin cross-drilled passages to extract heat from the caliper and reducethe temperature of the housing. These are restricted by the constraintsof machining, where the drillings have to be straight and then plugged.This restriction means that whilst a coolant can cool the caliper, it isnot as efficient as it could be due to flow resistance created by sharpedges within the cooling ducts and the large distance between thecooling ducts and the cylinder housing portions or seals of the caliper.

In view of the above, it is an object of the present invention toprovide a disc brake caliper body, which has improved coolingproperties. It is a further object of the invention to provide theimproved cooling effect without comprising the structural integrity ofthe brake caliper, which is subject to high loads during braking.

According to the present invention, there is provided a disc brakecaliper body comprising a mounting side bracket and a non-mounting sidebracket extending along a circumferential direction of the body, eachbracket being configured to hold at least one brake pad. The new discbrake caliper body further comprises at least one cooling duct formed byadditive manufacturing, the cooling duct being an integral part of thebrake caliper body and extending continuously along its length.

As the skilled person will understand, the directions of a brake caliperare usually specified in relation to the brake disc. As such, thecircumferential direction of the caliper is a direction parallel to thecircumference of the rotor disc. The radial direction refers to radialvectors originating in the centre of the brake disc and could also beentitled as a direction from the bottom to the top of the brake caliper.Finally, the lateral direction of the brake caliper refers to thedirection of the rotational axis of the brake disc. The lateraldirection, therefore, extends perpendicular to the circumferential andthe radial direction.

By manufacturing the cooling ducts in an additive manufacturing process,the ducts can be fully integrated into the brake caliper and compriseessentially any shape required for optimum cooling effects. To this end,it is preferable to produce the entire caliper body by additivemanufacturing. However, in some embodiments, only the cooling duct maybe produced by additive manufacturing, while other parts of the calipermay be formed by conventional machining steps. The additive layermanufactured cooling ducts can be provided significantly closer to otherfunctional parts of the caliper body (e.g. cylinder housings and seals)than conventionally known, machined cooling ducts. Finally, theinventive manufacturing method not only makes the cooling duct moreefficient in removing heat from the caliper body, but also offersimproved structural stiffness to the caliper and enables further weightreductions, which are particularly critical in racing applications. Thenew caliper body requires significantly less machining and no drillingfor production of the cooling duct. As such, there is no morerequirement for plug inserts to stop the hydraulic fluid from leakingout of the caliper body.

The term “continuous” or “continuously” in this specification refers toa mathematical meaning, namely that the cooling duct extends along apath that is differentiable at any point along the length of thehydraulic fluid duct. In simple terms, the cooling duct does not exhibitany sudden bends or corners. Rather, every point of the side wallextends smoothly along the length of the at least one hydraulic fluidduct. The continuous shape of the hydraulic fluid duct has the advantagethat pressure losses within the duct are minimised.

The at least one cooling duct is an integral part of the brake caliperbody. Accordingly the parts of the caliper comprising the cooling ductmay be entirely formed via additive manufacturing methods.

In another embodiment, the at least one cooling duct has a continuouslycurved shape, when viewed in plan. The curved shape of the cooling ductprevents cooling fluid from being trapped in corners or dead ends of theduct, which is conventionally known to increase the resistance to thecooling fluid flow provided by the master cylinder. In other words, thecooling duct of the present invention does not include sharp corners toavoid unnecessary resistance to the cooling fluid flow. Once again, theterm “continuously” refers to a curvature that is differentiable at anypoint along the along the length of the hydraulic fluid duct.

In another embodiment, the brake caliper body may comprise one or morebridging members connecting the mounting and non-mounting side bracketsin a substantially lateral direction, wherein the cooling duct extendsat least partly through the one or more bridging members. According tothis embodiment, the cooling duct can be used to transfer cooling fluid,such as the aforementioned routed air flow, from the mounting side ofthe caliper body towards the non-mounting side bracket, which isnormally at least partly obstructed by the brake disc. The cooling ductsof this embodiment can extend through one or all of the bridgingmembers, depending on the amount of cooling fluid required and theimpact on stiffness of the caliper. According to this aspect, at leastthe bridging member is produced by additive manufacturing.

In another embodiment, the one or more bridging members comprise a firstend bridge arranged and configured to connect leading ends of thebrackets and a second end bridge arranged and configured to connecttrailing ends of the brackets, wherein the cooling duct extends at leastpartly through the first and/or second end bridge. As will be describedin more detail below, this embodiment enables the pad gap to be freefrom ducting, which facilitates a quick and easy brake pad change,without having to avoid cooling ducts extending across the pad gap.

According to another embodiment, the cooling duct comprises a firstopening on a mounting side of the first end bridge and a second openingon a mounting side of the second end bridge, the cooling duct extendingthrough the first end bridge, the non-mounting side bracket and thesecond end bridge between the fluid opening and the second opening.According to this aspect, the fluid flow can be circulated around theinside of the caliper to enter and exit in the optimal position, such asthe mounting side of the brake caliper. This is particularly useful inconnection with the aforementioned cooling air flow, which is routedtowards the internal or mounting side of the brake disc.

According to another embodiment, the cooling duct extends in asubstantially U-shaped manner between the air inlet and the air outlet,when viewed in plan. The U-shaped design of the cooling duct has theadvantage that sharp turns and thus flow resistance within the coolingduct is avoided. Of course, the cooling duct may be constructed inanother shape but it is preferred to provide the cooling duct withsmooth corners to limit airflow resistance.

In another embodiment, the non-mounting side bracket comprises at leastone cylinder housing adapted to receive a corresponding brake piston,wherein at least a portion of the cooling duct extends around an outercircumference of the at least one cylinder housing. In other words, thecooling duct of this embodiment may be formed to surround the at leastone cylinder housing of the non-mounting side bracket between thenon-mounting side ends of the first and second end bridges.

According to another aspect, the one or more bridging members comprise acentral bridge arranged between a leading end and a trailing end of thecaliper body, the cooling duct extending at least partly through thecentral bridge. Accordingly, the cooling duct is centrally arranged withrespect to the caliper body and extends over the part of the body wherethe cylinder housings are situated and the most heat is created. Ofcourse, the cooling duct within the central bridge can be formed inaddition to the U-shaped cooling duct within the first and second endbridges described hereinbefore.

In another embodiment, the cooling duct extends between laterally innerfaces of the mounting and non-mounting side brackets. The laterallyinner faces of the mounting and non-mounting side brackets correspond tothe outlet side of the cylinder housings on which the brake pads aremounted. In other words, the laterally inner faces of the mounting andnon-mounting side brackets are the surfaces facing the brake disc inuse. Alternatively, the cooling duct may extend between a laterallyouter face of the mounting side bracket and cylinder housings of thenon-mounting side bracket. According to this embodiment, the coolingduct extends essentially across the whole caliper from its mounting sideend.

According to the alternative embodiment described hereinbefore, thecooling duct may comprise an air inlet arranged at the laterally outerface of the mounting side bracket along a radially outer end of thecaliper body, wherein the cooling duct may comprise an air outletlocated at a radially inner end of the caliper body. In other words, thecooling duct may be constructed to convey cooling fluid, such as coolingair, from a top end (radially outer end) of the mounting side brackettowards the lower end (radially inner end) of the non-mounting sidebracket and the mounting side bracket respectively. In this particularembodiment, the cooling duct may be arranged to steer the cooling fluidflow from a substantially lateral direction into a radial directionacross the cylinder housings of the side brackets.

In another embodiment, the cooling duct defines a cavity for conveyingcooling fluid, the cavity comprising supplementary structures extendingfrom an inner surface of the cooling duct, and wherein the structuresare formed by additive manufacturing. The supplementary structuresinside the cooling duct can be provided along the entire length of thecooling duct or just in predetermined places. The supplementarystructures can be used for a variety of different purposes, such asincreasing the surface area contacted by the cooling fluid, increasingthe stiffness in predetermined, preferably high stress, areas of thecooling duct, and inducing turbulent air flow.

According to another embodiment, at least parts of the supplementarystructures comprise a lattice structure having a partial skin. In thisapplication, the terms “skin” is intended to mean a portion having abulk density of substantially 100% of the material density from which itis formed. The term “lattice structure” is intended to mean a portionhaving a bulk density of 50% or less of material density from which itis formed. Advantageously, the lattice structure results in a strong,stiff, yet light design of the cooling duct. The skin may be external orinternal of the lattice structure. The lattice structure may be arrangedin parts of the cooling duct, which are subject to high bending stressesduring use of the caliper body.

Preferably, the bulk density of 50% or less of the lattice structure isachieved by providing voids within the lattice structure of a volumegreater than 50% of the cross-sectional area of the parts of the coolingduct, which comprise the lattice structure. More preferably, the voidshave a percentage void volume of at least 70%, in other words the bulkdensity of lattice structure is preferably 30% or less. Most preferably,the voids have a percentage void volume of 90%, corresponding to alattice bulk density of 10%. The lattice structure further providesgreater surface area and local turbulences to the air flow, which can beused to increase cooling efficiency of the caliper.

According to another embodiment, at least parts of the supplementarystructures comprise a plurality of vanes. The vanes may extend straightalong the length of the cooling duct or in an undulating manner. Similarto the lattice structure described hereinbefore, the vanes can providebending strength and stiffness to the cooling duct and caliper body inareas exposed to high bending stresses. Furthermore, the vanes increasethe surface area exposed to the cooling fluid flow to improve heattransfer from the caliper. The undulating vane design can be arrangedsuch that a balance between laminar flow for moving air cooling fluidaround the caliper, combined with local turbulences to maximise heattransfer can be obtained.

According to another embodiment, at least part of the supplementarystructures may comprise substantially column shape reinforcementmembers, the reinforcement members extending in a substantially radialdirection of the caliper body. The substantially column shapedreinforcement members will increase the stability of the cooling ductand brake caliper in areas of high bending stresses and provide for anincreased surface area to improve heat rejection. Similar to the vanestructures described hereinbefore, the columns can be located such thata balance between laminar flow for moving air around the caliper iscombined with local turbulences, which form particularly behind thecolumns, to maximise the heat transfer obtained by the cooling duct ofthe present invention.

Of course, it should be noted that the aforementioned supplementarystructures within the cooling duct are preferably only provided incertain areas, which either require improved stability or increasedsurface area or both. It is feasible to have more than one structurewithin the cooling duct, whereas other parts of the cooling duct may becompletely free of these structures. Alternative structures includedendritic forms, high chrome structures, body centred cubic structuresor gyroid structures. Preferably, any of the aforementioned structuresare formed such that a minimum cross-sectional area of one squaremillimetre remains within the cooling duct.

According to another embodiment, the mounting side bracket and/ornon-mounting side bracket comprise at least one cylinder housing adaptedto receive a corresponding brake piston, wherein cooling vanes extendaround an outer circumference of the at least one cylinder housing.According to one aspect, the cooling vanes of this embodiment compriseare attached to the outer diameter of the cylinder housings in areaswhere heat rejection is required to be maximised. While the vanes can beconstructed together with the remaining parts of the cooling duct bymeans of additive manufacturing, it is also feasible to manufacture thevanes separately and attach the latter to the cylinder housings of thecaliper retrospectively.

In another embodiment, the cooling duct is shaped such that, in use, aflow of cooling fluid is accelerated towards the cylinder housingportions. As such, the cooling duct may essentially be constructed inthe shape of a nozzle directed towards the cylinder housing portions ofthe respective bracket. In other words, the cooling duct may comprise avarying cross-sectional area along its length. This embodiment has theadvantage that the flow rate of the cooling fluid may be increased anddecreased according to the heat removal requirements along certain partsof the cooling duct.

While in the aforementioned embodiments the specific example of coolingair as the cooling fluid has been mentioned, it will be understood thatany other cooling fluid, such as water or other liquids and gasses couldbe utilised equivalently.

According to a second aspect of the present invention, there is provideda method of forming a brake caliper, said method comprising:

-   -   providing a powder bath;    -   fusing powder in said bath, layer by layer, according to a        digital record of a caliper body with a cooling duct, said        cooling duct being an integral part of the brake caliper body        and extending continuously along its length.

The digital record of the caliper body may be created using an FEsimulation of the brake caliper body. During FE simulation, boundaryconditions representing the load and heat development in use can be setto simulate the behaviour of the brake caliper body. Accordingly, oneembodiment includes providing the cooling duct in high temperatureand/or low stress areas of the caliper body simulated by the FEsimulation. In areas of high stress and high temperature, the coolingduct can be provided with the internal structures describedhereinbefore. As such, the method may include providing a latticestructure, vanes or reinforcement members within the cooling duct insaid areas.

Exemplary embodiments of brake calipers in accordance with the presentinvention will now be described in more detail with reference to theattached drawings. The drawings show:

FIG. 1a is a perspective view of a first embodiment of the brake caliperbody of the present invention;

FIG. 1b is a perspective cross-section of the caliper shown in FIG. 1a ,showing parts of the cooling ducts;

FIG. 1c is a plan view of the cross-section shown in FIG. 1 b;

FIG. 1d is a perspective view of a vertical cross-section of the firstembodiment of FIG. 1 a;

FIG. 2a is a perspective view of a second embodiment of the caliper bodyaccording to the present invention;

FIG. 2b is a cross-sectional plan view of the caliper body shown in FIG.2 a;

FIG. 2c is a perspective view of the cross-sectional illustration ofFIG. 2 a;

FIG. 2d shows a perspective view of a vertical cross-section of thecaliper body shown in FIG. 2 a;

FIG. 3a is a perspective view a third embodiment of the caliper of thepresent invention;

FIG. 3b is a cross-sectional plan view of the caliper body shown in FIG.3 a;

FIG. 3c is a perspective view of the cross-section shown in FIG. 3 b;

FIG. 3d is a vertical perspective cross-section of the caliper bodyshown in FIG. 3 a;

FIG. 4a is a perspective view of a fourth embodiment of a caliper bodyaccording to the present invention;

FIG. 4b is a cross-sectional plan view of the caliper body shown in FIG.4 a;

FIG. 4c is a perspective view of the cross-section shown in FIG. 4 b;

FIG. 4d is a perspective vertical cross-section of the caliper bodyshown n FIG. 4 a;

FIG. 5a is a perspective view of a fifth embodiment of the caliper bodyaccording to the present invention;

FIG. 5b is a cross-sectional plan view of the caliper body shown in FIG.5 a;

FIG. 5c is a perspective view of the cross-section shown in FIG. 5 b;

FIG. 5d is a perspective vertical cross-section of the caliper bodyshown in FIG. 5 a;

FIG. 6a is a perspective view of a sixth embodiment of the caliper bodyaccording to the present invention;

FIG. 6b is a perspective vertical cross-section of the caliper bodyshown in FIG. 6a ; and

FIG. 6c is a cross-sectional plan view of FIG. 6 b.

FIGS. 1a to 1d show a first embodiment of the brake caliper body of thepresent invention. The disc brake caliper body of the first embodimentcomprises a mounting side bracket 2 and a non-mounting side bracket 4,the mounting side bracket 2 has at least one, usually two, mountingholes 6 a and 6 b adapted to receive fastening members for attaching thecaliper body to the vehicle body. As such, the mounting side bracket isalso known as the body side bracket, whilst the non-mounting sidebracket can also be referred to as the cover side bracket.

As can be derived from FIG. 1b , for example, each of the brackets 2, 4comprises three cylinder housing portions 8 a, 8 b, 8 c, 9 a, 9 b, 9 c.The cylinder housing portions 8 a, 8 b, 8 c, 9 a, 9 b, 9 c of eitherbracket 2, 4 are arranged next to each other in the circumferentialdirection of the caliper body. In other words, their central axes arearranged along a common circumferential axis.

Each of the side brackets 2 and 4 has an inner surface 21, 41, whichfaces the brake disc, when the brake caliper body is mounted to straddlethe latter. The inner surfaces 21, 41 are part of laterally inner sidewalls that connect front apertures of the cylinder housing portions 8 a,8 b, 8 c, 9 a, 9 b, 9 c. Each side bracket 2, 4 further comprises anouter surface 22, 42, facing away from the brake disc, in use. The outersurfaces 22, 42 are part of laterally outer side walls connecting backends of the cylinder housing portions 8 a, 8 b, 8 c, 9 a, 9 b, 9 c. Asshown in FIG. 1a , the cylinder housing portions 9 a, 9 b and 9 c arecovered by a top cover 43 of the non-mounting side bracket 4, whereasthe cylinder housing portions 8 a, 8 b and 8 c are freely accessiblefrom the top and bottom of the brake caliper body 1. As will bedescribed in more detail below, the top cover 43 acts together with theaforesaid inner and outer side walls to form a cooling duct 50.

The cylinder housing portions 8 a, 8 b, 8 c, 9 a, 9 b, 9 c are arrangedbetween the laterally inner and outer walls of the side brackets 2, 4.The cylinder housing portions 8 a, 8 b, 8 c, 9 a, 9 b, 9 c areconfigured to receive brake pistons, which in turn are arranged to holda brake pad substantially parallel to the inner surface 21, 41 of therespective side brackets 2, 4.

FIG. 1a further shows bridging members 11 and 13. The bridging members11, 13 of the first embodiment shown in FIGS. 1a to 1d are arranged atcircumferential end portions of the brake caliper 1. As such, the brakecaliper body 1 comprises a leading end bridging member 11 and a trailingend bridging member 13, the leading bridging member 11 being arrangedalong a leading circumferential end portion of the caliper body 1 andthe trailing bridging member 13 being arranged along a trailingcircumferential end portion of the caliper body 1. The leading andtrailing ends of the caliper body 1 refer to the direction of rotationof the brake disc in use. During operation, parts of the brake disc willenter the caliper at the leading end, pass the brake pads at a centralportion and exit the caliper again at the trailing end.

As can further be derived from FIG. 1a , the bridging members 11 and 13connect the mounting and non-mounting side brackets 2, 4 in asubstantially lateral direction. This arrangement provides for a centralwindow 14, formed between the leading end bridging member 11, thetrailing end bridging member 13 and the inner surfaces 21, 41. As shown,the central window provides easy access to the apertures of the cylinderhousing portions 8 a, 8 b, 8 c, 9 a, 9 b, 9 c, and thus simplifyinspection and replacement of the brake pads (not shown). In the firstembodiment of FIGS. 1a to 1d , the brake caliper body 1 is depicted as amono-block caliper, that is the side brackets 2, 4 and the bridgingmembers 11, 13 are formed as a unitary structure. Alternatively, it isalso feasible to produce the caliper body of the present invention as amulti-piece/modular caliper.

FIG. 1b shows a perspective cross-section of the caliper shown in FIG.1a along a horizontal plane. A cooling duct 50, formed by means ofadditive manufacturing, extends through the caliper body 1. The coolingduct 50 is an integral part of the brake caliper body and in the firstembodiment extends through both bridging members 11, 13. The coolingduct 50 extends between a first opening 51 and a second opening 52. Theopenings 51 and 52 are both arranged on a mounting side of therespective bridging member. A first portion 54 of the cooling ductextends in a substantially lateral direction through the leading endbridging member 11 between the mounting side opening 51 and thenon-mounting side of the bridging member 11. A second portion 56 of thecooling duct 50 extends through the trailing end bridging member 13 in asubstantially lateral direction between the mounting side opening 52 andthe non-mounting side of the bridging member 13. At the non-mountingsides of the bridging members 11 and 13, the first and second portions54 and 56 of the cooling duct 50 are connected via a third portion 58.The third portion 58 is formed between the laterally inner and outersurface walls and the top cover 43 of the non-mounting side bracket 4and extends around the outer surface of the cylinder housing portions 9a, 9 b and 9 c. To facilitate air flow between side walls of adjacentcylinder housing portions 9 a, 9 b and 9 c, the cylinder housingportions 9 a, 9 b, 9 c are distanced in the circumferential directionand separated by slot likes openings 45 and 47 extending through thecaliper body 1 in the radial direction. The third portion 58 of thecooling duct 50, therefore, extends around the entire circumference ofeach of the cylinder housing portions 9 a, 9 b, 9 c. Similar slot likeopenings 25, 27 are provided between the cylinder housing portions 8 a,8 b and 8 c of the mounting side bracket.

As can be seen in FIG. 1c , the cooling duct 50 has a substantiallyU-shaped form, when viewed in plan. The corners of the duct between thefirst portion 54 and the third portion 58 or the second portion 56 andthe third portion 58 are rounded. This shape is obtained bymanufacturing the cooling duct 50 via additive manufacturing methodsrather than conventional machining steps. The rounded edges and cornersof the cooling duct 50 leads to a more laminar air flow through thecaliper body, which improves the cooling effect.

The cooling duct 50 of the first embodiment further has a varyingcross-section along its length. In particular, while the first andsecond portions 54 and 56 have a first, substantially identicalcross-section, the third portion has a second, larger cross-section. Thesecond cross-section is sufficient to surround the entirecircumferential surface of the cylinder housings 9 a, 9 b, 9 c. Thecorners of the U-shaped duct 50 shown in FIG. 1c are constructed astransitioning portions, in which the diameter of the cooling duct 50expands gradually from the first diameter to the second diameter.

A second embodiment of the brake caliper body according to the presentinvention is shown in FIGS. 2a to 2d . Corresponding parts of the firstand second embodiment are labelled with corresponding reference signsincreased by “100”. The caliper body 101 of the second embodiment againcomprises a mounting side bracket 102 and a non-mounting side bracket104, which are connected by leading and trailing end bridging members111, 113. The side brackets 102, 104 comprise three cylinder housingportions 108 a, 108 b, 108 c, 109 a, 109 b, 109 c.

In addition to the first and second end bridges 111, 113, the caliperbody 101 further comprises another bridging member arranged centrallybetween the leading end and the trailing end of the caliper body 101.This third bridging member is constructed as a central bridge 115 andextends in a substantially lateral direction between the non-mountingside bracket and the mounting side bracket 102, 104. As can be derivedfrom FIG. 2a , the central bridge 115 extends between the inner surfaces121, 141 of the side brackets 102 and 104 respectively.

A cooling duct 160 extends through the central bridge 115 in asubstantially lateral direction. The cooling duct 160 is provided with aplurality of vanes 162. The vanes 162 act to increase the surface areaon which the cooling air flow is applied. As particularly shown in FIGS.2b and 2c , the plurality of vanes 162 extend substantially straightalong the length of the cooling duct, that is, in a lateral direction ofthe caliper body 101.

The cooling duct 160 of the second embodiment has a varyingcross-section along its length. FIG. 2d shows that first and second endportions 164, 166 of the cooling duct 160 have a wider cross-sectionthan the central portion of the cooling 160. To this end, the first andsecond end portions 164, 166 have a flared profile to gradually increasethe cross-section of the cooling duct 160 towards the cylinder housingportions 108 a, 108 b, 108 c, 109 a, 109 b, 109 c. The flared first endportion 164 will increase fluid flow (e.g. air flow) intake along themounting side of the caliper body 1, while the flared second end portion166 is adapted to direct the cooling fluid towards the cylinder housingportions 109 a, 109 b, 109 c. In contrast to the first embodiment, itshould be noted that the cover or non-mounting side bracket 4 of thesecond embodiment does not comprise a top cover above the cylinderhousing portions 109 a, 109 b, 109 c.

A third embodiment of the brake caliper body is shown in FIGS. 3a to 3d. Corresponding parts of the first and third embodiment are labelledwith corresponding reference signs increased by “200”.

The brake caliper body 201 of the third embodiment is substantiallyidentical to the brake caliper body 101 of the second embodiment.However, a cooling duct 270 of the third embodiment, which extendsthrough central bridge 215 comprises a plurality of vanes 272 having asubstantially undulating shape. The undulating shape of vanes 272 isbest shown in FIG. 3b . The undulating vanes 272 comprise alternatingvalleys 278 and peaks 279. It is further shown that valleys 278 ofadjacent vanes are aligned along the length of the cooling duct 270. Inother words, each valley 278 of a first vane faces a valley of a second,adjacent vane. Similarly, the peaks of adjacent vanes are also alignedalong the length of the cooling duct 270. Accordingly, the width ofcooling channels 277 formed between the plurality of vanes issubstantially constant along the length of the cooling duct 270.Alternatively, it is also feasible to align peaks of one vane withvalleys of an adjacent vane, thereby creating cooling ducts with varyingflow diameters.

A fourth embodiment of the brake caliper body according to the presentinvention is shown in FIGS. 4a to 4d . Corresponding parts of the firstand fourth embodiment are labelled with corresponding reference signsincreased by “400”. The general structure of the brake caliper body 301of the fourth embodiment mainly corresponds to the shape of the caliperbody 101 and 201 of the second and third embodiments. However, incontrast to the second and third embodiments, the cooling duct 380 ofthe fourth embodiment comprises a plurality of column shapedreinforcement members 382 extending in a substantially radial directionof the caliper body 301 within the cooling duct 380. The column shapedreinforcement members 382 shown in FIG. 4b are arranged in offset rowsalong the length of cooling duct 380. In more detail, a first row 382 aof reinforcement members 382 has a plurality of reinforcement members382 arranged equidistantly along the length of the cooling duct 380. Asecond row 382 b of column shaped reinforcement members 382 is arrangedadjacent to the first row 382 a and, in turn, comprises a plurality ofcolumn shaped reinforcement members 382 arranged equidistantly along thelength of the cooling duct 380. The distance between the reinforcementmembers 382 in the first row 382 a is identical to the distance betweenreinforcement members 382 in the second, adjacent row 382 b. However,the adjacent first and second rows 382 a, 382 b are offset with respectto each other, such that reinforcement members 382 of the second row 382b are arranged between reinforcement members 382 of the first row 382 a.In particular, the reinforcement members 382 of the second row 382 b arearranged half-way between reinforcement members 382 of the first row 382a, along the length of the cooling duct 380. A third row 282 c, which isarranged adjacent to second row 382 b comprises column shapedreinforcement members 382, which are aligned with the reinforcementmember 382 of the first row 382 a.

A fourth embodiment of the caliper body according to the presentinvention is shown in FIGS. 5a to 5d . Corresponding parts of the firstand fifth embodiment are labelled with corresponding reference signsincreased by “400”. The caliper body 401 of the fifth embodimentcomprises mounting side and non-mounting side brackets 402, 404, both ofwhich are substantially closed along their upper end by top covers 443,423. A cooling duct 490 extends from the laterally outer surface 422 ofthe mounting side bracket 402 along the lateral direction of the caliperbody 401 via a central bridge 415. Air entering the cooling duct 490 viafluid inlet 491 can be distributed across the cylinder housing portions408 a, 408 b, 408 c of the non-mounting side bracket 402 and thecylinder housing portions 409 a, 409 b, 409 c of the mounting sidebracket 404 via central bridge 415. In other words, cooling duct 490extends in a substantially U-shaped manner when viewed from a lateralcross-section of the caliper body 401 (FIG. 5d ). The U-shaped coolingduct 490 comprises a first portion 493 extending in a radial directionaround the cylinder housing portions 408 a, 408 b, 408 c of thenon-mounting side bracket 402 and a second portion 495 extending aroundcylinder housing portions 409 a,409 b, 409 c of the non-mounting sidebracket 404. A third portion 497 formed by the central bridge 415extends in a substantially lateral direction between the first andsecond portions 493, 495, to direct cooling fluid flow that enters thefirst portion 493 via fluid inlet 491 towards the second portion 495.While FIGS. 5a to 5d show a substantially empty third portion 497 ofcooling duct 490, it is feasible to introduce vanes or columns, similarto the second to fourth embodiments discussed hereinabove, to increasethe cooling effect and/or increase stability of the central bridge 415.

A sixth embodiment of the present caliper body is shown in FIGS. 6a to6c . Corresponding parts of the first and sixth embodiment are labelledwith corresponding reference signs increased by “500”. The sixthembodiment of FIGS. 6a to 6c corresponds mostly to the second to fourthembodiments described hereinbefore. The caliper body 501 of the sixthembodiment comprises similar bridging members 511, 513, 515 to thebridging members of the second and fourth embodiments and a cooling duct590 extending through the central bridge 515.

In addition, the caliper body 501 comprises a plurality of cooling fins568 arranged along the outer circumference of the cylinder housings 508a, 508 b, 508 c, 509 a, 509 b, 509 c. As can be derived from FIG. 6c ,the cooling vanes 568 are arranged in parallel and extend in alongitudinal direction of the caliper body. FIG. 6c further shows thateach of the vanes 568 extends across all three cylinder housings 508 a,508 b, 508 c or 509 a, 509 b, 509 c respectively. The vanes 568 areprofiled to follow the shape of the outer circumference of the cylinderhousing 508 a, 508 b, 508 c, 509 a, 509 b, 509 c.

Similar to the cooling ducts described hereinbefore, the vanes 568 areproduced by additive manufacturing. The vanes 568 can either be formedtogether with the remaining parts of the caliper body 501 or as aseparate “add-on” structure, disposed onto the outer circumference ofthe cylinder housings 508 a, 508 b, 508 c, 509 a, 509 b, 509 c, afterthe latter has been produced. The vanes 568 of the sixth embodiment mayprincipally be added to any of the aforementioned embodiments shown inFIGS. 1a to 5 d.

The invention claimed is:
 1. A disc brake caliper body comprising: amounting side bracket and a non-mounting side bracket extending along acircumferential direction of the body, each bracket being configured tohold at least one brake pad, and at least one cooling duct formed byadditive manufacturing, the at least one cooling duct being an integralpart of the brake caliper body and extending continuously along itslength, wherein the at least one cooling duct is wholly encompassedwithin the disc brake caliper body, is wholly defined by material of thedisc brake caliper body, and is configured to provide a flow of coolantbetween an inlet port and an outlet port, wherein at least a portion ofthe at least one cooling duct has a continuously curved shape, whenviewed in plan, wherein the disc brake caliper body comprises a firstend bridge arranged and configured to connect leading ends of thebrackets and a second end bridge arranged and configured to connecttrailing ends of the brackets, the at least one cooling duct extendingat least partly through the first and second end bridge, and wherein theat least one cooling duct comprises a first fluid opening on a mountingside of the first end bridge and a second fluid opening on a mountingside of the second end bridge, the at least one cooling duct extendingthrough the first end bridge, the non-mounting side bracket and thesecond end bridge between the first opening and the second opening. 2.The disc brake caliper body of claim 1, wherein the at least one coolingduct is shaped such that, in use, a flow of cooling fluid is acceleratedtowards the cylinder housing portions.
 3. The disc brake caliper body ofclaim 1, wherein the at least one cooling duct comprises a varyingcross-sectional area along its length.
 4. The disc brake caliper body ofclaim 1, wherein the at least one cooling duct extends in asubstantially U-shaped manner between the first opening and the secondopening, when viewed in plan.
 5. The disc brake caliper body of claim 1,wherein the non-mounting side bracket comprises at least one cylinderhousing adapted to receive a brake piston, and wherein the at least onecooling duct extends around an outer circumference of the at least onecylinder housing.